U.S. patent application number 14/532372 was filed with the patent office on 2015-05-07 for fingerprint recognition sensor module having sensing region separated from asic.
The applicant listed for this patent is DREAMTECH CO., LTD. Invention is credited to Ho-Chul JOUNG, Jong-Hwa KIM, Young-Ho KIM, Jin-Seong LEE, Kyoung-Jun PARK.
Application Number | 20150125050 14/532372 |
Document ID | / |
Family ID | 53007090 |
Filed Date | 2015-05-07 |
United States Patent
Application |
20150125050 |
Kind Code |
A1 |
LEE; Jin-Seong ; et
al. |
May 7, 2015 |
FINGERPRINT RECOGNITION SENSOR MODULE HAVING SENSING REGION
SEPARATED FROM ASIC
Abstract
Disclosed is a fingerprint recognition sensor module including a
flexible printed circuit board. The flexible printed circuit board
includes a first sensing region formed with a first sensing input
unit, a second sensing region formed with a second sensing input
unit, a chip mounting region on which an ASIC is mounted to convert
a fingerprint sensed through the input units into a digital signal
and transmit the digital signal to a connector, and a connection
section to which the connector is connected. The chip mounting
region and the first and second sensing regions are separated from
each other on the same surface, and the flexible printed circuit
board is folded such that projection planes of the chip mounting
region and the first and second sensing regions are superposed one
above another.
Inventors: |
LEE; Jin-Seong; (Anyang-si,
KR) ; KIM; Jong-Hwa; (Seoul, KR) ; PARK;
Kyoung-Jun; (Cheonan-si, KR) ; JOUNG; Ho-Chul;
(Yongin-si, KR) ; KIM; Young-Ho; (Yongin-si,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DREAMTECH CO., LTD |
Seongnam-si |
|
KR |
|
|
Family ID: |
53007090 |
Appl. No.: |
14/532372 |
Filed: |
November 4, 2014 |
Current U.S.
Class: |
382/124 ;
29/841 |
Current CPC
Class: |
G06K 9/0002 20130101;
Y10T 29/49146 20150115; H05K 2201/10151 20130101; H05K 1/189
20130101 |
Class at
Publication: |
382/124 ;
29/841 |
International
Class: |
G06K 9/00 20060101
G06K009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 5, 2013 |
KR |
10-2013-0133635 |
Oct 24, 2014 |
KR |
10-2014-0144679 |
Claims
1. A fingerprint recognition sensing module having a recognition
function of using a fingerprint, comprising: a patterned flexible
printed circuit board comprising a first sensing region in which a
first sensing input unit is formed on the flexible printed circuit
board, a second sensing region in which a second sensing input unit
is formed on the flexible printed circuit board, an ASIC converting
a fingerprint sensed through the sensing input units into a digital
signal, a chip mounting region in which the ASIC is mounted on the
flexible printed circuit board, and a connector outputting the
digital signal from the ASIC to an outside of the fingerprint
recognition sensing module, wherein the chip mounting region and
the first and second sensing regions are formed in different
regions on the same surface of the flexible printed circuit
board.
2. A fingerprint recognition sensing module having a recognition
function of using a fingerprint, comprising: a patterned flexible
printed circuit board comprising a first sensing region in which a
first sensing input unit is formed on the flexible printed circuit
board, a second sensing region in which a second sensing input unit
is formed on the flexible printed circuit board, an ASIC converting
a fingerprint sensed through the sensing input units into a digital
signal, a chip mounting region in which the ASIC is mounted on the
flexible printed circuit board, and a connector outputting the
digital signal from the ASIC to an outside of the fingerprint
recognition sensing module, wherein the chip mounting region is
formed on a different surface from the first and second sensing
regions.
3. The fingerprint recognition sensing module according to claim 2,
wherein the first and second sensing regions are stacked on one
surface of the flexible printed circuit board and superposed one
above another, and the chip mounting region is separated from the
first and second sensing regions.
4. A fingerprint recognition sensing module having a recognition
function of using a fingerprint, comprising: a patterned flexible
printed circuit board comprising a first sensing region in which a
first sensing input unit is formed on the flexible printed circuit
board, a second sensing region in which a second sensing input unit
is formed on the flexible printed circuit board, an ASIC converting
a fingerprint sensed through the sensing input units into a digital
signal, a chip mounting region in which the ASIC is mounted on the
flexible printed circuit board, and a connector outputting the
digital signal from the ASIC to an outside of the fingerprint
recognition sensing module, wherein the first and second sensing
regions are formed on different surfaces of the flexible printed
circuit board.
5. The fingerprint recognition sensing module according to claim 4,
wherein the first and second sensing regions are formed on opposite
surfaces of the flexible printed circuit board, respectively, such
that projection planes of the first and second sensing regions are
superposed one above another.
6. A fingerprint recognition sensing module having a recognition
function of using a fingerprint, comprising: a patterned flexible
printed circuit board comprising a first sensing region in which a
first sensing input unit is formed on the flexible printed circuit
board, a second sensing region in which a second sensing input unit
is formed on the flexible printed circuit board, an ASIC converting
a fingerprint sensed through the sensing input units into a digital
signal, a chip mounting region in which the ASIC is mounted on the
flexible printed circuit board, and a connector outputting the
digital signal from the ASIC to an outside of the fingerprint
recognition sensing module, wherein the chip mounting region and
the first and second sensing regions have the same projection
region when superposed one above another.
7. The fingerprint recognition sensing module according to claim 1,
further comprising: a stiffener between the stacked sensing input
units and the ASIC to secure flatness and strength of the sensing
input units, wherein the flexible printed circuit board is folded
such that projection planes of the chip mounting region and the
first and second sensing regions are superposed one above
another.
8. The fingerprint recognition sensing module according to claim 7,
wherein the stiffener has a flat surface to be attached to the
sensing regions.
9. The fingerprint recognition sensing module according to claim 7,
wherein the stiffener has a convex curved surface to be attached to
the sensing regions to correspond to a shape of a finger.
10. The fingerprint recognition sensing module according to claim
7, wherein the stiffener is interposed between the sensing regions
and the chip mounting region.
11. The fingerprint recognition sensing module according to claim
7, wherein the stiffener has a receiving slot formed on a surface
thereof facing the chip mounting region and receiving the ASIC.
12. The fingerprint recognition sensing module according to claim
7, wherein a functional coating layer is formed on surfaces of the
stacked first and second sensing regions to increase a fingerprint
recognition rate.
13. The fingerprint recognition sensing module according to claim
12, wherein the functional coating layer comprises a primer layer,
a paint layer, and a UV curing layer, or a primer layer, a paint
layer, and a baking paint coating layer.
14. The fingerprint recognition sensing module according to claim
13, wherein the functional coating layer further comprises a high-k
dielectric material layer between the primer layer and the paint
layer.
15. The fingerprint recognition sensing module according to claim
12, wherein the functional coating layer has a thickness of 10
.mu.m to 50 .mu.m to increase a sensing rate.
16. The fingerprint recognition sensing module according to claim
12, wherein the functional coating layer comprises a high-k
dielectric material to increase electrostatic capacity.
17. The fingerprint recognition sensor module according to claim 7,
further comprising: a bezel surrounding the stacked sensing input
units and a side surface of the stiffener attached thereto.
18. The fingerprint recognition sensor module according to claim
15, wherein the bezel is formed of a metallic material conducting
electricity, and a portion of the bezel which a user touches with a
finger is coated with a nonconductive material.
19. The fingerprint recognition sensor module according to claim
17, wherein the functional coating layer further comprises: a
nano-coating layer surrounding a sensing plane of the stacked
sensing input units and a surface of the bezel to prevent
infiltration of moisture.
20. The fingerprint recognition sensor module according to claim 1,
wherein the first sensing input unit is a transmitter and the
second sensing input unit is a receiver, or the first sensing input
unit is a receiver and the second sensing input unit is a
transmitter.
21. A method of fabricating a fingerprint recognition sensing
module, comprising: (a) preparing a flexible printed circuit board
and an ASIC to be mounted on the flexible printed circuit board,
and mounting the ASIC on the flexible printed circuit board, the
flexible printed circuit board comprising a first sensing region, a
second sensing region, a chip mounting region on which the ASIC is
mounted, and a connection section to which a connector is
connected; (b) attaching a stiffener to a rear surface of the
superposed first and second sensing regions to secure flatness
thereof; (c) forming a coating layer on surfaces of the first and
second sensing regions; (d) attaching a bezel to a periphery of the
superposed first and second sensing regions; and (e) connecting a
connector to the connection section of the flexible printed circuit
board.
22. The method according to claim 21, wherein (b) attaching the
stiffener comprises: attaching the stiffener after the first and
second sensing regions are superposed one above another by folding
the flexible printed circuit board.
23. The method according to claim 21, wherein (c) forming the
coating layer comprises: attaching a functional coating layer
formed through a separate process to the surfaces of the first and
second sensing regions.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to Korean Patent
Application No. 10-2013-0133635 filed on Nov. 5, 2013, and Korean
Patent Application No. 10-2014-0144679 filed on Oct. 24, 2014, and
all the benefits accruing therefrom under 35 U.S.C. .sctn.119, the
contents of which is incorporated by reference in its entirety.
BACKGROUND
[0002] 1. Technical Field
[0003] The present invention relates to a fingerprint recognition
sensor module, and more particularly, to a fingerprint recognition
sensor module having a sensing region separated from an ASIC to
enhance sensing performance and process yield.
[0004] 2. Description of the Related Art
[0005] Fingerprint recognition technologies are widely used in user
registration and authentication procedures to prevent security
breaches. Particularly, fingerprint recognition technologies are
applied to personal and systematic network defense, protection of
various content and data, and stable access control.
[0006] In recent years, as a variety of mobile devices including
smartphones and tablet PCs are widely used, personal information
and content recorded and stored in the mobile devices are
frequently leaked regardless of user intention.
[0007] In the related art, fingerprint recognition functions are
applied to some mobile devices such as smartphones and notebooks.
However, fingerprint scanners are attached to mobile devices such
that they are visible to the eye, thereby causing security problems
and limitations to design of the mobile devices.
[0008] The present invention is aimed at providing a fingerprint
recognition sensor module that may be applied as a home key to
mobile devices. Korean Patent Publication No. 10-2002-0016671 A
(published on Mar. 6, 2002) discloses a portable information
terminal in which a fingerprint recognition module is embedded, and
a control method thereof.
BRIEF SUMMARY
[0009] It is one aspect of the present invention to provide a
fingerprint recognition sensor module having excellent sensing
performance and high process yield.
[0010] It is another aspect of the present invention to provide a
fingerprint recognition sensor module in which sensing regions are
formed to be separated from an ASIC, thereby ensuring flatness of a
sensing plane not only before coating but also in an end
product.
[0011] It is a further aspect of the present invention to provide a
fingerprint recognition sensor module that can enhance fingerprint
sensing performance and recognition rates by ensuring flatness of a
sensing region.
[0012] It is yet another aspect of the present invention to provide
a touch type fingerprint recognition sensor module in which
transmitter and receiver regions respectively corresponding to
first and second sensing regions of a sensing unit are superposed
one above another, thereby reducing manufacturing costs.
[0013] It is yet another aspect of the present invention to provide
a fingerprint recognition sensor module in which a stiffener is
attached to a rear surface of a sensing region to secure flatness
of a sensing plane, and a surface of the stiffener is formed to be
convex, thereby achieving stable fingerprint sensing.
[0014] The present invention is not limited to these aspects, and
other aspects and advantages of the present invention not mentioned
above will be understood through the following description, and
more clearly understood from exemplary embodiments of the present
invention. In addition, it will be easily appreciated that the
aspects and advantages are realized by features and combination
thereof as set forth in claims.
[0015] In accordance with one aspect of the present invention, a
fingerprint recognition sensor module includes a flexible printed
circuit board, which includes: a first sensing region formed with a
first sensing input unit; a second sensing region formed with a
second sensing input unit; a chip mounting region on which an ASIC
is mounted, the ASIC converting a fingerprint sensed through the
input units into a digital signal and transmitting the digital
signal to a connector; and a connection section to which the
connector is connected, wherein the chip mounting region and the
first and second sensing regions are separated from each other on
the same surface, and the flexible printed circuit board is folded
such that projection planes of the chip mounting region and the
first and second sensing regions are superposed one above
another.
[0016] In accordance with another aspect of the present invention,
a fingerprint recognition sensor module includes a flexible printed
circuit board, which includes: a first sensing region formed with a
first sensing input unit; a second sensing region formed with a
second sensing input unit; a chip mounting region on which an ASIC
is mounted, the ASIC converting a fingerprint sensed through the
input units into a digital signal and transmitting the digital
signal to a connector; and a connection section to which the
connector is connected, wherein the chip mounting region and the
first and second sensing regions are separated from each other, the
first and second sensing regions are formed on one surface, and the
chip mounting region is formed on the other surface of the flexible
printed circuit board, in which the flexible printed circuit board
is folded such that projection planes of the chip mounting region
and the first and second sensing regions are superposed one above
another.
[0017] In accordance with a further aspect of the present
invention, a fingerprint recognition sensor module includes a
flexible printed circuit board, which includes: a first sensing
region formed with a first sensing input unit; a second sensing
region formed with a second sensing input unit; a chip mounting
region on which an ASIC is mounted, the ASIC converting a
fingerprint sensed through the input units into a digital signal
and transmitting the digital signal to a connector; and a
connection section to which the connector is connected, wherein the
chip mounting region and the first and second sensing regions are
separated from each other, the first sensing region is formed on
one surface, the second sensing region is formed on the other
surface, and the chip mounting region is formed on one of both
surfaces of the flexible printed circuit board, in which the
flexible printed circuit board is folded such that projection
planes of the chip mounting region and the first and second sensing
regions are superposed one above another.
[0018] In accordance with yet another aspect of the present
invention, a fingerprint recognition sensor module includes a
flexible printed circuit board, which includes: a first sensing
region formed with a first sensing input unit; a second sensing
region formed with a second sensing input unit; a chip mounting
region on which an ASIC is mounted, the ASIC converting a
fingerprint sensed through the input units into a digital signal
and transmitting the digital signal to a connector; and a
connection section to which the connector is connected, wherein the
first and second sensing regions are formed on both surfaces of the
same region of the flexible printed circuit board, respectively,
and the chip mounting region is formed to be separated from the
first and second sensing regions, in which the flexible printed
circuit board is folded such that projection planes of the chip
mounting region and the first and second sensing regions are
superposed one above another.
[0019] In accordance with yet another aspect of the present
invention, a fingerprint recognition sensor module includes a
flexible printed circuit board, which includes: a first sensing
region formed with a first sensing input unit; a second sensing
region formed with a second sensing input unit; a chip mounting
region on which an ASIC is mounted which embodies a signal sensed
through the input units; and a connection section to which the
connector is connected, wherein the first and second sensing
regions are stacked on one surface of the same region of the
flexible printed circuit board and the chip mounting region is
formed to be separated from the first and second sensing regions,
in which the flexible printed circuit board is folded such that
projection planes of the chip mounting region and the first and
second sensing regions are superposed one above another.
[0020] The fingerprint recognition sensing module may further
include a stiffener attached to the stacked first and second
sensing regions to secure flatness and strength of the sensing
regions.
[0021] The stiffener may have a flat or convex curved surface to be
attached to the sensing regions, and the convex curved surface may
correspond to the shape of a finger.
[0022] The stiffener may be interposed between the superposed
sensing regions and the chip mounting region and may have a
receiving slot formed on a surface thereof facing the chip mounting
region and receiving the ASIC.
[0023] A functional coating layer may be formed on surfaces of the
stacked first and second sensing regions to increase a fingerprint
recognition rate.
[0024] The functional coating layer may have a thickness of 10
.mu.m to 50 .mu.m to increase a sensing rate.
[0025] The functional coating layer may include a high-k dielectric
material layer.
[0026] The fingerprint recognition sensor module may further
include a bezel surrounding the stacked first and second sensing
regions and a side surface of the stiffener attached thereto.
[0027] The bezel may be formed of a metallic material conducting
electricity, and a portion of the bezel which a user touches with a
finger may be coated with a nonconductive material.
[0028] In accordance with yet another aspect of the present
invention, a method of fabricating a fingerprint recognition
sensing module includes: (a) preparing a flexible printed circuit
board and an ASIC to be mounted on the flexible printed circuit
board, and mounting the ASIC on the flexible printed circuit board,
the flexible printed circuit board comprising a first sensing
region, a second sensing region, a chip mounting region on which
the ASIC is mounted, and a connection section to which a connector
is connected; (b) attaching a stiffener to a rear surface of the
superposed first and second sensing regions to secure flatness
thereof; (c) forming a coating layer on surfaces of the first and
second sensing regions; (d) attaching a bezel to a periphery of the
first and second sensing regions; and (e) connecting the connector
to the connection section of the flexible printed circuit
board.
[0029] The method may further include bonding the first and second
sensing regions through folding after operation (a) and forming a
shape of the fingerprint recognition sensor module by cutting the
flexible printed circuit board formed in an array shape in which
the sensing regions are bonded.
[0030] Attaching the stiffener may include attaching the stiffener
after the first and second sensing regions are superposed one above
another by folding the flexible printed circuit board.
[0031] Forming the coating layer may include attaching a functional
coating layer formed through a separate process to the surfaces of
the first and second sensing regions.
[0032] As described above, embodiments of the invention provide
fingerprint recognition sensor modules in which sensing regions are
separated from a chip mounting region on which an ASIC is mounted,
thereby enhancing sensing sensitivity.
[0033] In addition, embodiments of the invention provide
fingerprint recognition sensor modules in which a stiffener is
bonded to a rear surface of a sensing region to secure flatness
thereof, and a stiffener surface is formed to be convex so that the
sensing region bonded thereto is made convex to enhance contact
performance between a finger and the sensing region, thereby
increasing sensing sensitivity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The above and other aspects, features, and advantages of the
present invention will become apparent from the detailed
description of the following embodiments in conjunction with the
accompanying drawings, in which:
[0035] FIG. 1 is a plan view of a flexible printed circuit board
for fabrication of a fingerprint recognition sensor module
according to a first embodiment of the present invention;
[0036] FIG. 2 is a side view of the flexible printed circuit board
according to the first embodiment of the invention;
[0037] FIG. 3 is a longitudinal sectional view showing a stack
structure of the flexible printed circuit board according to the
first embodiment of the invention;
[0038] FIG. 4 is a side view of a flexible printed circuit board
for fabrication of a fingerprint recognition sensor module
according to a second embodiment of the present invention;
[0039] FIG. 5 is a side view of a flexible printed circuit board
for fabrication of a fingerprint recognition sensor module
according to a third embodiment of the present invention;
[0040] FIG. 6 is a side view of a flexible printed circuit board
for fabrication of a fingerprint recognition sensor module
according to a fourth embodiment of the present invention;
[0041] FIG. 7 is a side view of a flexible printed circuit board
for fabrication of a fingerprint recognition sensor module
according to a fifth embodiment of the present invention;
[0042] FIG. 8 is a plan view of a flexible printed circuit board
for fabrication of a fingerprint recognition sensor module
according to a sixth embodiment of the present invention;
[0043] FIG. 9 is an exploded perspective view showing a flexible
printed circuit board and a stiffener of a fingerprint recognition
sensor module according to the present invention;
[0044] FIG. 10 is a perspective view showing an attachment state of
the flexible printed circuit board and the stiffener of the
fingerprint recognition sensor module according to the present
invention;
[0045] FIG. 11 is a perspective view showing a state in which the
stiffener is attached to the flexible printed circuit board of the
fingerprint recognition sensor module according to the present
invention and a chip mounting region is folded toward a bottom
surface of the stiffener;
[0046] FIG. 12 is a section view showing one example of a
stiffener, having a convex curved surface, of a fingerprint
recognition sensor module according to the present invention;
[0047] FIG. 13 is an exploded perspective view showing a state
before attachment of a bezel to a fingerprint recognition sensor
module according to the present invention;
[0048] FIG. 14 is a perspective view showing a state after
attachment of the bezel to the fingerprint recognition sensor
module according to the present invention; and
[0049] FIG. 15 is a flowchart showing a method of fabricating a
fingerprint recognition sensor module according to the present
invention.
TABLE-US-00001 [0050]<List of Reference Numerals> 110:
Flexible printed circuit board 112: First sensing region 114:
Second sensing region 116: Chip mounting region 118: Connection
section 120: ASIC 140: Stiffener 150: Bezel 160: Connector
DETAILED DESCRIPTION
[0051] Hereinafter, exemplary embodiments of the present invention
will be described in to detail with reference to the accompanying
drawings. Here, all terms and words used in the specification and
claims should not be construed as limited to common or lexical
definitions and should be interpreted as definitions and concepts
corresponding to the spirit and scope of the present invention
based on the principle that inventors may pertinently define
concepts of the terms in order to describe their own disclosures in
the best way. In addition, since embodiments described in the
specification and configurations shown in the accompanying drawings
are merely exemplary embodiments of the present invention and do
not represent the spirit of the present invention, it should be
understood that there may be various equivalents and modifications
can be made at the time of filing the present application.
[0052] In general, a flexible printed circuit board for fabrication
of a fingerprint recognition sensor module is formed on one surface
thereof with a chip mounting region on which a chip for fingerprint
recognition (hereinafter, referred to as an ASIC) is mounted and on
the other surface thereof with sensing regions opposite to the chip
mounting region. The ASIC is formed of a hard material such as
ceramic or silicon, whereas the flexible printed circuit board is
formed of a thin soft material, which causes flexure at a bonding
interface between the ASIC and the flexible printed circuit board.
As a result, it is difficult to secure flatness of a sensing plane.
That is because flexure occurs at a bonding interface between
heterogeneous materials due to shrinkage or expansion.
[0053] Flexure on a sensing plane that is a surface of a sensing
region causes degradation in sensing performance and poor external
appearance of an end product.
[0054] The present invention is characterized in that, in designing
a flexible printed circuit board, sensing regions are separated
from a chip mounting region on which an ASIC is mounted, thereby
ensuring flatness of the sensing regions.
[0055] Hereinafter, fingerprint recognition sensor modules having a
sensing region separated from an ASIC according to embodiments of
the invention will be described in detail with reference to the
accompanying drawings.
[0056] FIG. 1 is a plan view of a flexible printed circuit board
for fabrication of a fingerprint recognition sensor module
according to a first embodiment of the invention.
[0057] Referring to FIG. 1, a flexible printed circuit board 110
for fabrication of a fingerprint recognition sensor module
according to the first embodiment of the invention includes a first
sensing region 112 formed with a first sensing input unit, a second
sensing region 114 formed with a second sensing input unit, a chip
mounting region 116 on which an ASIC operated in response to
signals sensed through the sensing input units is mounted, and a
connection section 118 to which a connector for connection to a
device is attached.
[0058] The first and second sensing input units are functionally
separated from each other. One of the first and second sensing
input units may be a transmitter and the other may be a
receiver.
[0059] A continuous current flow in the transmitter induces a
uniform magnetic field. Here, when the transmitter is touched with
a finger, there is a variation in the current flow in the
transmitter so that distribution of the magnetic field changes with
the shape of a fingerprint. The receiver senses the change in the
magnetic field distribution of the transmitter and transmits the
sensed change to the ASIC.
[0060] The first sensing input unit may be a transmitter, and the
second sending input unit may be a receiver, or vice versa.
[0061] FIG. 2 is a side view of the flexible printed circuit board
for fabrication of a fingerprint recognition sensor module
according to the first embodiment of the invention.
[0062] FIG. 2 shows an ASIC 120 mounted on the chip mounting region
of the flexible printed circuit board. Referring to FIG. 2, in the
flexible printed circuit board 110 according to the first
embodiment, the first and second sensing regions 112, 114 and the
chip mounting region 116 are formed on the same surface of the
flexible printed circuit board. In this embodiment, a low-priced,
single-sided substrate may be used instead of a high-priced,
double-sided substrate.
[0063] FIG. 3 is a sectional view showing a stack structure of the
flexible printed circuit board for fabrication of a fingerprint
recognition sensor module according to the first embodiment of the
invention.
[0064] As described above, in the fingerprint recognition sensor
module according to the first embodiment, the first and second
sensing regions 112, 114 and the chip mounting region 116 are
separated from each other on the same surface of the flexible
printed circuit board to be folded. More specifically, the flexible
printed circuit board is folded such that projection areas of the
first and second sensing regions 112, 114 are superposed one above
another, and then folded such that the chip mounting region 116 on
which the ASIC 120 is mounted is placed below the superposed
sensing regions.
[0065] When the fingerprint recognition sensor module is formed by
folding the flexible printed circuit board in this way, the first
and second sensing regions 112, 114 and the chip mounting region
116 are superposed one above another. In the embodiment shown in
FIG. 3, the first sensing region 112 is superposed on the second
sensing region 114. Alternatively, the second sensing region 114
may be superposed on the first sensing region 112.
[0066] FIG. 4 is a side view of a flexible printed circuit board
for fabrication of a fingerprint recognition sensor module
according to a second embodiment of the invention.
[0067] The second embodiment is the same as the first embodiment in
that first and second sensing regions 112, 114 and a chip mounting
region 116 are formed to be separated from each other. However, in
the first embodiment, the first and second sensing regions 112, 114
and the chip mounting region 116 are formed on the same surface,
whereas in the second embodiment, the first and second sensing
regions 112, 114 are formed on the same surface and the chip
mounting region 116 is formed on a surface opposite to the surface
on which the sensing regions 112, 114 are formed.
[0068] As in the first embodiment, the first and second sensing
regions 112, 114 and the chip mounting region 116 are also
superposed one above another in the finished fingerprint
recognition sensor module according to the second embodiment, and
thus repetitive descriptions thereof will be omitted.
[0069] FIG. 5 is a side view of a flexible printed circuit board
for fabrication of a fingerprint recognition sensor module
according to a third embodiment of the invention.
[0070] The third embodiment is the same as the aforementioned
embodiments in that first and second sensing regions 112, 114 and a
chip mounting region 116 are formed to be separated from each
other. However, in the third embodiment, the first and second
sensing regions 112, 114 are formed on different surfaces.
[0071] Although the chip mounting region 116 and the first sensing
region 112 are formed on the same surface in FIG. 5, the chip
mounting region 116 and the second sensing region 114 may also be
formed on the same surface.
[0072] As in the aforementioned embodiments, the first and second
sensing regions 112, 114 and the chip mounting region 116 are also
superposed one above another in the finished fingerprint
recognition sensor module according to the third embodiment.
[0073] FIG. 6 is a side view of a flexible printed circuit board
for fabrication of a fingerprint recognition sensor module
according to a fourth embodiment of the present invention, and FIG.
7 is a side view of a flexible printed circuit board for
fabrication of a fingerprint recognition sensor module according to
a fifth embodiment of the present invention.
[0074] In the fourth embodiment, first and second sensing regions
112, 114 are formed on both surfaces of the same region,
respectively, and a chip mounting region 116 is separated from the
first and second sensing regions.
[0075] In the fifth embodiment, first and second sensing regions
112, 114 are stacked on one surface of the same region, and a chip
mounting region 116 is separated from the first and second sensing
regions.
[0076] In the aforementioned embodiments, the fingerprint
recognition sensor modules are manufactured by forming the first
and second sensing regions 112, 114 in the separated regions on the
same surface, followed by superposing the first sensing region 112
on the second sensing region 114 through folding. In contrast, in
the fourth embodiment, the first and second sensing regions 112,
114 are formed on both surfaces of the same region, and in the
fifth embodiment, the first and second sensing regions 112, 114 are
stacked on one surface of the same region, thereby omitting a
process of superposing the sensing regions through folding.
[0077] Although the chip mounting region 116 and the first sensing
region 112 are illustrated as being formed on the same surface in
FIG. 6, the chip mounting region 116 and the second sensing region
114 may also be formed on the same surface.
[0078] Although the chip mounting region 116 and the first and
second sensing region 112,114 are illustrated as being formed on
different surfaces in FIG. 7, the chip mounting region 116 and the
second sensing region 112,114 may also be formed on the same
surface.
[0079] The fourth and fifth embodiments are different from the
aforementioned embodiments in that the sensing regions are
superposed one above another in manufacture of the flexible printed
circuit board. However, as in the aforementioned embodiments, the
sensing regions are formed to be separated from the chip mounting
region 16, thereby suppressing flexure of the sensing regions. In
addition, as in the aforementioned embodiments, the first and
second sensing regions 112, 114 and the chip mounting region 116
are also superposed one above another in a finished fingerprint
recognition sensor module.
[0080] FIG. 8 is a plan view of a flexible printed circuit board
for fabrication of a fingerprint recognition sensor module
according to a sixth embodiment of the invention.
[0081] Although the first and second sensing regions 112, 114 and
the chip mounting region 116 are longitudinally arranged in a line
in the first embodiment, first and second sensing regions 112, 114
may also be laterally arranged, as shown in FIG. 8.
[0082] In addition, although the first sensing region 112 is
illustrated as being arranged at a right side of the second sensing
region 114 in the embodiment of FIG. 8, the first sensing region
112 may also be arranged at a left side of the second sensing
region 114.
[0083] FIG. 9 is an exploded perspective view showing a flexible
printed circuit board and a stiffener of a fingerprint recognition
sensor module according to the present invention, FIG. 10 is a
perspective view showing an attachment state of the flexible
printed circuit board and the stiffener of the fingerprint
recognition sensor module according to the present invention, and
FIG. 11 is a perspective view showing a state in which the
stiffener is attached to the flexible printed circuit board of the
fingerprint recognition sensor module according to the present
invention and a chip mounting region is folded toward a bottom
surface of the stiffener.
[0084] In the fingerprint recognition sensor modules according to
the present invention, a superposed sensing regions 113 are formed
by superposing the first sensing region on the second sensing
region through folding the flexible printed circuit board (first to
third embodiments), by forming the first and second sensing regions
on both surfaces of the flexible printed circuit board,
respectively, (fourth embodiment), or by stacking the first and
second sensing regions on one surface of the flexible printed
circuit board (fifth embodiment). In another way, the sensing
regions 113 are formed on one surface of a flexible printed circuit
board, in which first and second sensing functional units may be
intermingled with each other.
[0085] However, the superposed sensing regions 113 are merely a
doubly superposed flexible printed circuit board or a single
flexible printed circuit board. Therefore, the superposed sensing
regions 113 are likely to have a crooked surface due to ductility
thereof.
[0086] According to the present invention, a stiffener is attached
to the superposed sensing regions 113 to secure flatness of the
superposed sensing regions 113.
[0087] Although a stiffener 140 may be attached to the superposed
sensing regions 113 by thermal fusion, adhesives or double-sided
adhesive tapes may also be used instead of thermal fusion.
[0088] A functional coating layer is formed on one surface of the
superposed sensing regions 113. The stiffener 140 may be attached
to the other surface of the superposed sensing regions 113 before
formation of the functional coating layer, thereby omitting or
reducing a flatting process during formation of the functional
coating layer.
[0089] The functional coating layer may include a primer layer, a
painting layer, and a UV curing layer, and the respective coating
layers may have enhanced permittivity by adding a high-k dielectric
material thereto.
[0090] The functional coating layer preferably has a thickness of
10 .mu.m to 50 .mu.m to secure sensing performance.
[0091] The stiffener 140 for increasing flatness and strength of
the sensing regions 113 may be formed of metallic foil or a
synthetic resin injection-molded material.
[0092] Although the stiffener 140 may be formed of any material
capable of ensuring flatness and strength thereof, it is
advantageous in terms of cost and usability that the stiffener 140
be formed of a plastic injection-molded material. The stiffener 140
also needs thermal resistance in consideration of attachment to the
sensing regions through thermal fusion.
[0093] In addition, the stiffener 140 may have a receiving slot 142
capable of receiving an ASIC 120. The receiving slot is formed in a
region of the stiffener 140 on which the ASIC 120 is superposed,
thereby reducing the thickness and size of the fingerprint
recognition sensor module.
[0094] The stiffener 140 attached to the superposed sensing regions
113 may have a flat surface as shown in FIGS. 9 to 11 or a convex
curved surface as shown in FIG. 12. In this case, the stiffener 140
preferably has a height (h) of about 1 mm. When the sensing regions
113 have a convex central portion, pressing force increases upon
touching the sensing regions 113 with a finger, thereby enhancing
sensing performance. However, when the stiffener 140 has an
excessive height (h), a contact area is reduced and local pressure
applied to the sensing regions 113 is increased, whereby sensing
performance can be somewhat degraded.
[0095] Reference numeral 115 in FIG. 9 denotes a folding region of
the flexible printed circuit board. The folding region may be
folded forward or backward.
[0096] FIG. 13 is an exploded perspective view showing a state
before attachment of a bezel to a fingerprint recognition sensor
module according to the present invention, and FIG. 14 is a
perspective view showing a state after attachment of the bezel to
the fingerprint recognition sensor module according to the present
invention.
[0097] Referring to FIGS. 13 and 14, the fingerprint recognition
sensor module may include a bezel 150 that surrounds superposed
sensing regions. The bezel 150 functions as an ornament to enhance
aesthetics and protect the sensing regions.
[0098] The bezel may be formed of a metallic material capable of
conducting electricity, without any specific limitation. An upper
portion of the metallic bezel 150 which a user touches with a
finger is preferably coated with a nonconductive material to
prevent electric shock and ensure sensing reliability.
[0099] In contrast, a lower portion of the bezel 150 adjacent to an
ASIC 120 is preferably formed to conduct electricity to prevent
damage of the ASIC 120 due to static electricity. To this end, the
bezel may be completely coated with a nonconductive material and
then only the lower portion of the bezel may be formed to conduct
electricity through additional laser processing.
[0100] A connector 160 is attached to a connection section 118 of
the flexible printed circuit board 110, and the fingerprint
recognition sensor module is connected to a device, such as a
cellular phone, through the connector 160.
[0101] FIG. 15 is a flowchart showing a method of fabricating a
fingerprint recognition sensor module according to the present
invention.
[0102] The method of manufacturing a fingerprint recognition sensor
module according to the present invention includes: mounting an
ASIC on a flexible printed circuit board including a first sensing
region, a second sensing region, a chip mounting region on which
the ASIC is mounted, and a connection section to which a connector
is attached (S110); bonding the first and second sensing regions
through folding such that the first and second sensing regions are
superposed one above another and attaching a stiffener to a rear
surface of the superposed sensing regions through thermal fusion
(S120); sequentially forming a primer layer, a paint layer, and a
UV curing layer on a surface of the superposed sensing regions
(S130); attaching a bezel to the superposed sensing regions to
surround a periphery of the superposed sensing regions (S140); and
connecting a connector to the connection section of the flexible
printed circuit board (S150).
[0103] In operation S110 of mounting the ASIC on the flexible
printed circuit board, the flexible printed circuit board may be
prepared, as shown in FIG. 13, by manufacturing a plurality of
flexible printed circuit boards in an array shape, followed by
separating the flexible printed circuit boards through
punching.
[0104] The ASIC may be mounted on the flexible printed circuit
board by anisotropic conductive paste (ACP) bonding, anisotropic
conductive adhesive (ACA) bonding, flip chip bonding, or surface
mount technology.
[0105] In operation S120 of superposing the sensing regions and
attaching the stiffener, the first and second sensing regions may
be bonded to each other using a double-sided adhesive tape, and the
stiffener may be attached to the superposed sensing regions by
thermal fusion using a thermal bonding tape. The thermal bonding
tape is temporarily bonded to the flexible printed circuit boards
of the array shape, cut together in punching the flexible printed
circuit boards, and bonded with the stiffener by thermal
fusion.
[0106] In operation S130 of forming the functional coating layer,
the primer layer, the painting layer, and the UV curing layer are
sequentially formed on a surface of the sensing regions.
[0107] The primer layer serves to enhance adhesive performance
between the paint layer and the flexible printed circuit board,
considering that the paint layer is not well attached to the
flexible printed circuit board made of polyimide. The primer layer
may be formed of urethane or a UV coating material. In addition,
the flexible printed circuit board may be subjected to surface
treatment using plasma and then the primer layer may be formed on
the flexible printed circuit board.
[0108] The method of manufacturing a fingerprint recognition sensor
module may include coating a high-k dielectric material on the
primer layer.
[0109] The high-k dielectric material may be ceramic powder
including at least one of alumina (Al.sub.2O.sub.3), silica
(SiO.sub.2), barium peroxide (BaO.sub.2), barium oxide (BaO),
titanium oxide (TiO.sub.2), barium titanate (BaTiO.sub.3),
BaSrTiO.sub.3, and tantalum oxide (TaAOB).
[0110] Oxides with a PA-based perovskite structure, oxides with a
PB-based perovskite structure, or oxides with a perovskite
structure including at least one of other potential metals may be
used as the high-k dielectric material. Specifically, the oxides
with the PA-based perovskite structure (e.g., BaZrO.sub.3,
SrTiO.sub.3, BaSnO.sub.3, CaSnO.sub.3, and PbTiO.sub.3), the oxides
with the PB-based perovskite structure (e.g., MgO, MgTiO.sub.3,
NiSnO.sub.3, CaTiO.sub.3, and Bi.sub.2(SnO.sub.3)), and the oxides
with the perovskite structure including other potential metals may
be used as the high-k dielectric material.
[0111] In addition, a material including one or more of the ceramic
power and one or more of the oxides may be used as the high-k
dielectric material.
[0112] In this operation, the high-k dielectric material may be
deposited by chemical vapor deposition (CVD) or physical vapor
deposition (PVD).
[0113] Specifically, CVD or PVD may be used for deposition of the
high-k dielectric material.
[0114] CVD is a process in which a material to be deposited (i.e.,
a high-k dielectric material) is injected in a gaseous state into a
reaction chamber and deposited onto a substrate inside the reaction
chamber through high-temperature decomposition or high-temperature
chemical reaction.
[0115] There are thermal CVD, plasma enhanced CVD, photo CVD, and
the like based on reaction energy sources, and there are
atmospheric pressure CVD, low pressure CVD, and the like based on
process pressures. A high-k dielectric material may be deposited
through any one of these CVD methods depending upon required
deposition conditions.
[0116] PVD is a method of forming a thin film in a vaporized atomic
form using a material to be deposited (i.e. a high-k dielectric
material) without chemical reaction in a vacuum.
[0117] As well known in the art, there are sputtering,
electron-beam evaporation, thermal evaporation, laser molecular
beam epitaxy, and pulsed laser deposition. A high-k dielectric
material may be deposited through any one of PVD methods depending
upon required deposition conditions.
[0118] The paint layer is implemented with paint, such as carbon
black ink or white ink, corresponding to a color of device for
which the fingerprint recognition sensor module is employed and
making the fingerprint recognition sensor module indistinguishable
to the eye. The painting layer preferably has a thickness of 2
.mu.m to 8 .mu.m. When the painting layer has a thickness of less
than 2 .mu.m, painting quality and shielding performance are
difficult to secure, and when the painting layer has a thickness of
more than 8 .mu.m, sensing sensitivity is likely to be reduced.
[0119] The UV curing layer for endowing gloss and hardness with a
surface may be implemented by coating a UV curing resin in a glossy
or matte form, followed by UV curing the resin. The UV curing layer
preferably has a thickness of 15 .mu.m to 40 .mu.m. When the UV
curing layer has a thickness of less than 15 .mu.m, gloss and
hardness are difficult to secure, and when the painting layer has a
thickness of more than 40 .mu.m, sensing sensitivity is likely to
be reduced. Baking paint may also be coated instead of the UV
curing layer. The baking paint may include one of melamine baking
paint, acrylic baking paint, and fluoride resin baking paint. Due
to excellent high-temperature resistance, a baking paint coating
layer formed by coating baking paint does not deform and discolor
even when surface mounting technology (SMT) is used as a back-end
of line for the fingerprint recognition sensor module.
[0120] When a high-k dielectric material is mixed in formation of
the functional coating layer, electrostatic capacity is enhanced.
Therefore, in spite of thickness increase, the functional coating
layer may maintain the same level of performance as when having a
small thickness, thereby ensuring reliability of the fingerprint
recognition sensor module. In other words, each functional coating
layer may be formed by mixing a high-k dielectric material (e.g.,
ceramic powder with a high dielectric constant) with the material
of which the functional coating layer is formed.
[0121] Here, a suitable amount of the high-k dielectric material is
mixed with the material of the functional coating layer to increase
permittivity of the functional coating layer, and the same high-k
dielectric material as that coated onto the primer layer may be
used.
[0122] A nano-coating layer may be additionally formed after the
formation of the UV curing layer. The nano-coating layer is a
functional coating layer for preventing moisture from infiltrating
into the fingerprint recognition sensor module from the
outside.
[0123] If moisture infiltrates into the fingerprint recognition
sensor module due to use conditions and user mistakes, corrosion is
induced, thereby reducing a lifespan thereof.
[0124] In addition, damage, such as corrosion, degrades an
excellent fingerprint recognition rate (e.g., a fingerprint
recognition rate of 90% or more) ensured when the product is
released, thereby causing low performance.
[0125] Therefore, the nano-coating layer is additionally formed to
solve the problem of moisture infiltration, thereby preventing a
decrease in fingerprint recognition rate due to internal
corrosion.
[0126] The nano-coating layer may include a material containing at
least one component of a fluorine compound, a fluoro-based resin,
and Parylene. In addition, well-known components having a
waterproofing function may be used as a composite of the
nano-coating layer.
[0127] In operation S130 of forming the functional coating layer,
the functional coating layer may be separately formed and then
attached.
[0128] For example, a functional coating layer may be formed by
sequentially stacking a UV top coating layer, a paint layer, and a
shielding layer on a release film, separated from the release film
when completely cured, and then aligned with and attached to a
sensing plane of the fingerprint recognition sensor module.
[0129] The functional coating layer may be attached to the
fingerprint recognition sensor module using a curable resin. A
thermosetting resin or a UV curable resin may be used as the
curable resin. Alternatively, an epoxy resin or an acrylic resin
may also be used as the curable resin.
[0130] Since the flat and cured functional coating layer is
attached to the sensing plane, a concave-convex pattern on the
sensing plane is covered with the curable resin layer formed of a
curable resin, thereby keeping a surface of the functional coating
layer flat.
[0131] In operation S140 of attaching a bezel to the superposed
sensing regions, a bonding method using an epoxy resin may be used.
When the bezel is attached to the periphery of the sensing regions
using an epoxy resin, the epoxy resin seals a space between the
bezel and the periphery of the sensing regions, thereby preventing
moisture infiltration into the space and consequently, enhancing
water tightness and durability.
[0132] In operation S150 of connecting a connector, the connector
is attached to the connection section of the flexible printed
circuit board to connect the fingerprint recognition sensor module
to a product. The connector may be connected to the connection
section directly or through a separate connector link substrate
according to product design. The connector (or connector link
substrate) may be bonded to the connection section by surface mount
technology (SMT), anisotropic conductive adhesive (ACA) bonding, or
anisotropic conductive film (ACF) bonding. In this case, a metallic
bottom plate may be attached to a bottom surface of the connector
to be connected to the connection section. The metallic bottom
plate may remove static electricity by ensuring a ground and
increase strength of the bottom surface of the fingerprint
recognition sensor module. In addition, an electromagnetic
interference (EMI) film may be attached to the metallic bottom
plate to prevent damage or malfunction due to static
electricity.
[0133] Although some embodiments have been described herein, it
should be understood by those skilled in the art that these
embodiments are given by way of illustration only, and that various
modifications, variations, and alterations can be made without
departing from the spirit and scope of the invention. Therefore,
the scope of the invention should be limited only by the
accompanying claims and equivalents thereof.
* * * * *